Dice the chicken breast into small, even bite-sized pieces and season with sea salt and black pepper.
Finely mince the garlic and ginger, and thinly slice the scallions, keeping the white and green parts separate.
Heat a large non-stick skillet or wok over medium-high heat with half of the avocado oil.
Whisk the egg in a small bowl, pour into the hot skillet, and scramble quickly until just set; remove the egg from the pan and set aside.
Add the remaining avocado oil to the same skillet and add the chicken pieces, sautéing until golden brown and cooked through.
Stir in the garlic, ginger, and the white parts of the scallions, cooking for 30 seconds until fragrant.
Add the frozen peas and carrots to the skillet and cook for 2 minutes until tender-crisp.
Add the cooked brown rice to the pan, breaking up any clumps, and toss with the chicken and vegetables.
Drizzle the tamari and toasted sesame oil over the rice, stirring constantly for 2-3 minutes to allow the rice to slightly crisp.
Fold the scrambled egg back into the mixture and garnish with the green parts of the scallions before serving.